Linkage arrangement

Abstract

A linkage arrangement ( 10 ) is provided for moveably connecting an attachment ( 6 ) to a work machine ( 8 ). The linkage arrangement ( 10 ) includes linkage group ( 12 ) having an upper arm ( 14 ) with a machine pivot point ( 20 ) for connecting to the work machine ( 8 ) and an attachment pivot point ( 22 ) for connecting to the attachment ( 6 ). The linkage group ( 12 ) further has a lower arm ( 16 ) with a machine pivot point ( 24 ) for connecting to the work machine ( 8 ) and an attachment pivot point ( 26 ) for connecting to the attachment ( 6 ). An actuator ( 30 ) extends between the upper and lower arms ( 14, 16 ), whereby during normal operation an increase in the length of the actuator ( 30 ) results in the attachment ( 6 ) being lowered relative to the work machine ( 8 ).

The invention claimed is: 
     
       1. A linkage arrangement for moveably connecting an attachment to a machine, said linkage arrangement comprising:
 a first linkage group having an upper arm with a machine pivot point for connecting to the machine and an attachment pivot point for connecting to the attachment, and a lower arm with a machine pivot point for connecting to the machine and an attachment pivot point for connecting to the attachment; 
 a variable length actuator extending between the upper and lower arms, the variable length actuator being configured such that during normal operation an increase in the length of the actuator results in the attachment being lowered relative to the machine; 
 wherein at least one of the upper arm and the lower arm has a dual wall construction and wherein at least a portion of the actuator is positioned between the two walls of the dual wall construction. 
 
     
     
       2. A linkage arrangement according to  claim 1 , wherein the actuator has
 a) an upper pivot point generally located between the machine and attachment pivot points of the upper arm, and 
 b) a lower pivot point generally located between the machine and attachment pivot points of the lower arm. 
 
     
     
       3. A linkage arrangement according to  claim 2 , wherein the upper pivot point of the actuator is located adjacent the machine pivot point of the upper arm. 
     
     
       4. A linkage arrangement according to  claim 2 , wherein the lower pivot point of the actuator is located adjacent the attachment pivot point of the lower arm. 
     
     
       5. A linkage arrangement according to  claim 1 , further comprising a second linkage group substantially similar to the first linkage group, the first and second linkage groups being connected via a support structure extending between the first and second linkage groups. 
     
     
       6. A linkage arrangement for moveably connecting an attachment to a machine, said linkage arrangement comprising:
 a first linkage group having an upper arm with a machine pivot point for connecting to the machine and an attachment pivot point for connecting to the attachment, and a lower arm with a machine pivot point for connecting to the machine and an attachment pivot point for connecting to the attachment; 
 a variable length actuator extending between the upper and lower arms, and configured such that during normal operation an increase in the length of the actuator results in the attachment being lowered relative to the machine; 
 a second linkage group substantially similar to the first linkage group, the first and second linkage groups being connected via a support structure extending between the first and second linkage groups, 
 wherein the support structure comprises at least first and second tubular elements extending between upper arms of the first and second linkage groups. 
 
     
     
       7. A linkage arrangement according to  claim 6 , wherein two plate members are connected to the first and second tubular elements and the upper arms of the first and second linkage groups to form a box section. 
     
     
       8. A linkage arrangement according to  claim 6 , wherein at least one plate member is connected to the first and second tubular elements and upper arms of the first and second linkage groups. 
     
     
       9. An attachment configured for coupling to a machine via a linkage arrangement, the linkage arrangement including:
 a first linkage group including an upper arm with a machine pivot point for connecting to the machine and an attachment pivot point for connecting to the attachment, and a lower arm with a machine pivot point for connecting to the machine and an attachment pivot point for connecting to the attachment; and 
 a variable length actuator extending between the upper and lower arms and configured such that during normal operation an increase in the length of the actuator results in the attachment being lowered relative to the machine; 
 wherein the attachment includes a foot plate with a rake angle that changes during raising and lowering, wherein the rake angle decreases during lowering of the attachment relative to the machine due to the kinematics of the linkage arrangement, and wherein at least one of the upper arm and the lower arm has a dual wall construction and wherein at least a portion of the actuator is positioned between the two walls of the dual wall construction. 
 
     
     
       10. The attachment of  claim 9 , wherein the variable length actuator includes:
 a) an upper pivot point generally located between the machine and attachment pivot points of the upper arm, and 
 b) a lower pivot point generally located between the machine and attachment pivot points of the lower arm. 
 
     
     
       11. The attachment of  claim 10 , wherein the upper pivot point of the actuator is located adjacent the machine pivot point of the upper arm. 
     
     
       12. The attachment of  claim 10 , wherein the lower pivot point of the actuator is located adjacent the attachment pivot point of the lower arm. 
     
     
       13. The attachment of  claim 9 , wherein the linkage arrangement further includes a second linkage group substantially similar to the first linkage group, the first and second linkage groups being connected via a support structure extending between the first and second linkage groups. 
     
     
       14. An attachment configured for coupling to a machine via a linkage arrangement, the linkage arrangement including:
 a first linkage group including an upper arm with a machine pivot point for connecting to the machine and an attachment pivot point for connecting to the attachment, and a lower arm with a machine pivot point for connecting to the machine and an attachment pivot point for connecting to the attachment; 
 a variable length actuator extending between the upper and lower arms and configured such that during normal operation an increase in the length of the actuator results in the attachment being lowered relative to the machine; and 
 a second linkage group substantially similar to the first linkage group, the first and second linkage groups being connected via a support structure extending between the first and second linkage groups; 
 wherein the attachment includes a foot plate with a rake angle that changes during raising and lowering, wherein the rake angle decreases during lowering of the attachment relative to the machine due to the kinematics of the linkage arrangement, and wherein the support structure includes at least first and second tubular elements extending between upper arms of the first and second linkage groups, and wherein two plate members are connected to the first and second tubular elements and the upper arms of the first and second linkage groups to form a box section.